Many biological molecules are flexible in solution, which can be assessed by nuclear magnetic resonance (NMR). As a part of our continuing effort to develop computational methods to elucidate molecular conformers based on NMR data, we proposed a new approach, a multiple-conformer refinement with simultaneous determination of each conformer's population. The implementation of this approach is based on combination of two programs, DNAminiCarlo and PDQPRO. DNAminiCarlo performs energy minimization and Metropolis Monte Carlo simulations for nucleic acids, and PDQPRO determines the optimal probability distribution for a predefined pool of potential conformers by finding the best fit between calculated and experimental NMR parameters. The Computer Graphics Laboratory resources are necessary for our project for graphical representation of structural ensembles.